It would be helpful to be able to group layers inside the online map, similar to the way you can group layers within ArcMap. For instance: have a group for utilities and inside that group you have your sanitary, storm, lighting, electric, gas etc.. so that there is not a long layer list in your legend and if they want to look at the utilities, they would only have to check the one box instead of 20 something boxes. The ability to turn layers on and off as a default for your map within the group would be fantastic.
Working for a municipality and previously a DOT, sometimes different departments might need to see things from another department and having everything separate makes that difficult. For instance, Somebody from planning might need to see the utilities or street lights, or public works might need to see zoning information, or the parks department might need to see ROW to know if their trees need to be trimmed etc..
This would allow for you to have several things on one map instead of seperate maps for every single thing. Possibly when you click on the group, a query could pop up that is related to the newly checked group.
Doing this would save traffic through your server and bandwidth and keep things simple for the end user. I hope I am explaining this correctly. I have attached a map I am currently using from a third party software. I was able to do this and the internal map get's used daily from all the departments and everybody loves it. Unfortunately it was sunset, but I am really surprised I couldn't find this request on here. Hopefully it isn't a duplicate.
This Idea has been marked as a duplicate of Group layers for ArcGIS online . Please continue to share your feedback and upvotes on the original idea.